Base-lock for extension-tables.



H. M. HANSON. BASE LOOK FOR EXTENSION TABLES.

APPLICATION FILED SEPT. 7, 1909.

Patented J an.'24, 1911.

2 SHEETS-SHEET 1.

HENRY M. HANSON, OF JANESVILLE, WISCONSIN.

BASE-LOCK FOR EXTENSION-TABLES.

Specification of Letters Patent.

' Patented Jan. 24, 1911.

Application filed September 7, 1909. Serial No. 516,572.

To all whom it may concern:

Be it known that I, HENRY M. HANsoN,

a citizen of the United States, residing at Janesville, in the county of Rock and State of WVisconsin, have invented certain new and useful Improvements in Base-Locks for Extension-Tables, of which the following is a specification.

This invention relates to extension tables of that type employing a divided base or pedestal support; and has for its object to provide a simple and improved device for securely locking together the mating halves of the base and also for insuring the perfect meeting or registration of the base sections.

The lock of my invention is of that type that is located internally of the pedestal and is manually operable by a suitable lever or handle located beneath the upper surface of the table top.

The device of the invention and its mode of manipulation and advantages will be readily understood when considered in connection with the accompanying drawings, illustrating one practical mechanical embodiment thereof, and in which Figure 1 is a perspective elevation of a table, interiorly broken out to show my improved lock and its location and mode of application. Fig. 2 is a fragmentary top plan View, on an enlarged scale, with the table top removed and the divided bridgepiece and pedestal-sections shown slightly separated. Fig. 3 is an inner edge view of the parts shown at the left in F 1g. 2; and Fig. 1 is a similar outer edge view of the parts shown at the left in Fig. 2.

Referring to the drawings, 5 and 6 designate the mating sections of an ordinary divided pedestal, and 7 and 8 the mating sections of the usual divided bridge mounted directly upon the upper ends of the pedestal sections 5 and 6, respectively.

9 and 10 designate as entireties the usual table-top sections which are mounted upon the bridge sections 7 and 8 with capacity for longitudinal extension by the usual series of slots indicated at 11.

Referring now to the structural features of my improved lock, 12 designates a vertical spindle that is j ournaled at its lower end in a bracket 13 rigidly secured to the inner surface of the pedestal section 5 and proj ecting inwardly and radially thereof. The upper end of the spindle 12 is similarly journaled in the bridge-piece 7 and in a bearing plate 14 secured to the upper side thereof. ()n the lower end of the spindle 12, just above the bracket 13 is fixed a pinion 15 adapted for engagement with a short rack 16 that is secured at its outer end to the inner wall of the pedestal section 6 and projects inwardly and approximately normally of the latter in a horizontal plane just above that of the bracket 13; and this latter is provided with an upwardly and inwardly turned guide and keeper 17 adapted to engage the back and upper side of the rack.

Fast on the upper end of the spindle 12, directly above its bearing plate 14, is a ratchet disk 18; and loosely j ournaled on the upper end of the spindle 12 directly above the ratchet disk 18 is an operating arm or lever 19, to which is pivoted, on its under side, a pawl 20, the tail of which is engaged by a compression spring 21 having an abutment against a lug 22 secured to the lever and normally pressing the tail of the oawl outwardly, thereby forcing the nose 0 the pawl into engagement with the ratchet disk 18. Fixedly mounted in and rising from the bearing plate 1 1 is a short stud 23 which, when the handle is thrown to one extreme of its swinging movement, engages the inner edge of the pawl and forces it out of engagement with the ratchet, as plainly shown in Fig. 2.

Secured at its ends as by screws 24 to the top of the bridge-piece 7 is a generally areshaped guide 25 for the handle 19, this guide having a longitmlinal slot 26 through which the handle project-s. The lower edge of the slot is serrated, or formed with a series of ratchet teeth 27, best shown in Figs. 3 and 1; and at one end of said lower edge, somewhat beyond the scries of ratchet teeth, is formed a single locking notch 28. The handle is provided on its lower side with a depending tooth 29 adapted for engagement with the teeth 27 to lock the handle against accidental movement in a direction to unlock the ratchet 18, this position being shown in Fig. 1; and also adapted for engagement, when in an extreme position, with the notch 28 to lock the handle against accidental movement in the opposite direction, or into locking relation to the ratchet 18, this latter position being shown in Figs. 2, 3 and 4:. The handle is pivoted on the upper end of the spindle 12 with suflicient looseness to have a limited vertical play; and the slot 26 is wide enough to permit such limited -to be closed, the two halves are pushed together until the rack-bar 16 comes into engagement with the pinion 15. The sections may then be brought into completely closed position either by pushing them farther to- "gether, or by raising the handle 19 out of engagement with the underlying teeth 27 20 and working said handle back and forth, thus effecting the rotation of the spindle 12 through the pawl 20 and ratchet 18. This latter operation is preferably performed to effect the final closing movement of the sections, since it provides a powerful means of drawing the sections together very snugly. When the sections have thus been fully brought into closed position, the handle is allowed to drop, carrying the tooth 29 into 30 engagement with the serrated lower edge of the slot 26, as shown in Fig. 1, whereby the .table sections are positively locked against displacement until the handle is raised. hen it is desired to extend the table sec tions, the handle is raised and swung to the extreme position shown in Figs. 2, 3 and 4, in which position the pawl 20 is retracted from the ratchet 18 by engagement with the fixed stud 23, thus unlocking the mechanism; and this unlocked position is maintained by dropping the tooth 29 into the notch 28 of the handle guide. The table sec- "tions may then be pulled apart to the desired extent without any interference from the locking mechanism.

. From the foregoing it will be seen that my device provides both a secure lock to insure against accidental separation of the table sections when in closed position, and a positive and powerful means for drawing said sections snugly into closed position.

Without confining myself to the exact and specific details of structure, which may be more or less varied by the mechanic skilled in the art without departing from the principle of the invention, I claim:

1. A base lock for extension tables, comprising a rotatable spindle vertically mounted in one section of a divided pedestal base, cooperating members secured to said spindle and the other section of said divided base, respectively, and adapted to be drawn together upon rotation of said spindle, a ratchet disk fast on said spindle, an operating arm pivoted on said spindle and carrying a pawl engaging and actuating said ratchet disk, means for locking said operating arm in ratchet-engaging position, and means for automatically disengaging said pawl from said ratchet disk on swinging said operating arm to an extreme angular position, substantially as described.

2. A base lock for extension tables, comprising a rotatable spindle vertically mounted in one section of a divided pedestal base, cooperating members secured to said spindle and the other section of said divided base, respectively, and adapted to be drawn together upon rotation of said spindle, a ratchet disk fast on said spindle, an operating arm pivoted on said spindle and carrying a pawl engaging and actuating said ratchet disk, means for locking said operating arm in ratchet-engaging position, means for automatically disengaging said pawl from said ratchet disk on swinging said operating arm to an extreme angular position, and means for locking said operating arm in said extreme angular position, substantially as described.

3. A base lock for extension tables, comprising a rotatable spindle vertically mounted in one section of a divided pedestal base, a pinion fast on the lower end of said spindle, a rack secured to the other section of said divided base and cooperating with said pinion, a ratchet disk fast on the upper end of said spindle, an operating arm pivoted on the upper end of said spindle and carrying a pawl engaging and actuating said ratchet disk, a slotted arc-shaped guide through which said arm passes, the slot whereof is serrated on one edge and formed with a locking notch near one end thereof, a locking tooth on said arm adapted to engage said serrated edge and locking notch, and a fixed stud adapted to disengage said pawl from said ratchet disk when said arm is moved to carry its tooth into engagement with said locking notch of the guide, substantially as described.

HENRY M. HANSON.

Witnesses A. P. BURNHAM, WM. RUGER, J r. 

